In FreeBSD before 11.2-STABLE(r340854) and 11.2-RELEASE-p5, the NFS server lacks a bounds check in the READDIRPLUS NFS request. Unprivileged remote users with access to the NFS server can cause a resource exhaustion by forcing the server to allocate an arbitrarily large memory allocation.

In FreeBSD before 11.2-STABLE(r340268) and 11.2-RELEASE-p5, due to incorrectly accounting for padding on 64-bit platforms, a buffer underwrite could occur when constructing an ICMP reply packet when using a non-standard value for the net.inet.icmp.quotelen sysctl.

In FreeBSD before 11.2-STABLE(r338987), 11.2-RELEASE-p4, and 11.1-RELEASE-p15, due to insufficient memory checking in the freebsd4_getfsstat system call, a NULL pointer dereference can occur. Unprivileged authenticated local users may be able to cause a denial of service.

In FreeBSD before 11.2-STABLE(r338983), 11.2-RELEASE-p4, 11.1-RELEASE-p15, 10.4-STABLE(r338984), and 10.4-RELEASE-p13, due to insufficient initialization of memory copied to userland in the getcontext and swapcontext system calls, small amounts of kernel memory may be disclosed to userland processes. Unprivileged authenticated local users may be able to access small amounts privileged kernel data.

In FreeBSD before 11.2-STABLE(r338986), 11.2-RELEASE-p4, 11.1-RELEASE-p15, 10.4-STABLE(r338985), and 10.4-RELEASE-p13, due to improper maintenance of IPv6 protocol control block flags through various failure paths, an unprivileged authenticated local user may be able to cause a NULL pointer dereference causing the kernel to crash.

In FreeBSD before 11.2-RELEASE, a stack guard-page is available but is disabled by default. This results in the possibility a poorly written process could be cause a stack overflow.

In FreeBSD before 11.2-RELEASE, multiple issues with the implementation of the stack guard-page reduce the protections afforded by the guard-page. This results in the possibility a poorly written process could be cause a stack overflow.

In FreeBSD 11.x before 11.1-RELEASE and 10.x before 10.4-RELEASE, the qsort algorithm has a deterministic recursion pattern. Feeding a pathological input to the algorithm can lead to excessive stack usage and potential overflow. Applications that use qsort to handle large data set may crash if the input follows the pathological pattern.

In FreeBSD before 11.1-STABLE, 11.2-RELEASE-p3, 11.1-RELEASE-p14, 10.4-STABLE, and 10.4-RELEASE-p12, insufficient validation in the ELF header parser could allow a malicious ELF binary to cause a kernel crash or disclose kernel memory.

In FreeBSD before 11.2-RELEASE, an application which calls setrlimit() to increase RLIMIT_STACK may turn a read-only memory region below the stack into a read-write region. A specially crafted executable could be exploited to execute arbitrary code in the user context.